Final answer:
Certificates in AWS Certificate Manager must be created in the same region as the AWS services they will be used with, except for global services like CloudFront which require certificates to be created in the US East region.
Step-by-step explanation:
When using AWS Certificate Manager (ACM), the certificates must be created in the same AWS region as the resources you want to use with the certificate. AWS services such as Elastic Load Balancing, Amazon CloudFront, and API Gateway require that the ACM certificate be in the same region as the service. For services like CloudFront, where the distribution is global, ACM certificates must still be created in the US East (N. Virginia) region. It's important to choose the right region for the certificate to avoid issues with deployment and to ensure that the resources can correctly reference and use the ACM certificate.
Additionally, if you have resources in multiple regions that require a certificate, you will need to create a certificate in each of those regions. Understanding these regional requirements is important for a smooth integration between ACM and other AWS services.